Biometric capture devices (fingerprint scanners, cameras, etc.) are used to authenticate people. In some cases, authentication is verification, i.e., wherein a person specifies who they are and the devices are used to verify that a person presented is indeed that person by comparing the presented person's biometric data to biometric data stored for the person specified. In other cases authentication is identification, wherein biometrics of a presented person are tested against a body or database of biometric data for many people to find a match, thereby identifying the presented person as the matching person. This can be done if, for example, the body of biometric data associates sets of biometric data with personal identifiers (name, ID number, alias or the like). For example, a presented person might present a fingerprint, which is then compared to each fingerprint in the body of biometric data to find a match. If a match is found, the presented person can be presumed to have the personal identifier (name, ID number, alias, or the like) associated with the matching fingerprint in the body of biometric data.
Biometric data, not by way of limitation, might include fingerprints, facial features, face images, voice, voice prints, iris scans, retina scans, body signals, signatures, blood typing, DNA scans, protein assays and the like. One or more of these might be used. Authentication can be done for any purpose, such as security, tracking, crime prevention, customization of other systems to user preferences, communication and other purposes.
The problem of identification in a biometric authentication or identification system can be difficult. For example, where identification is used to identify employees of a large organization when entering a building or other secured area, a biometric identification system must operate quickly to capture biometric data from a presented person and attempt a match of that presented person's biometric data against a possibly large set of biometric data of all the employees of the large organization. Identification must be done quickly, because the typical entry point would otherwise become a bottleneck for traffic. Identification is further complicated by the realities of biometric data not being amenable to being captured exactly in the same manner each time.